The domain is checked with the following:
your_specified_domains
.split(',')
.map(a => new RegExp(a.trim().toLowerCase()))
.filter(a => a.test(running_domain_where_api_lives));
It is not possible right now. Windy API provides "only" our Leaflet extensions and map tools. It allows you to use Windy map layers and read its data. Forecast is not a part of that. We are sorry.